Abstract

The Best "Optics" for JWST

Brenda Frye (University of Arizona)

Rolf Jansen, Stu Wyithe, Chris Conselice, Seth Cohen, Adi Zitrin, Dan Coe, Mehmet Alpaslan, Simon Driver, Aaron Robotham, Robert Barone-Nugent, Rogier Windhorst

A picture is emerging in which star forming galaxies are rare at the highest redshifts (z > 10) owing to the nearly catastrophic drop in the galaxy number counts for z > 7-8. Coupled with this, the recent downward revision of the Planck polarization optical depth suggests a rather low epoch of reionization (z < 8 for the case that it is instantaneous). The implication is that even with JWST the characteristic luminosities may potentially be too low to detect the highest redshift objects. This result was unexpected at the time of JWST design. Such a handicap imposed on detecting the First Light sources, one of the four prime directives of JWST, is a cause of much concern. Of the different approaches to get past this limitation, the one we have chosen is to take advantage of the lensing effect to sample the background sources ~2-3 magnitudes further down the faint end of the luminosity function. We address the pressing need to find the best lensing clusters for JWST in two ways: (1) to identify the most massive (M~10^15 Msun), most dark-matter dense (c = 3-8) lenses in existing data, and (2) to search for submillimeter giant arcs in the fields of all-sky survey data such as Planck and Herschel as pointers to entirely new massive lensing cluster fields. We present here our best candidates to promote as additional ‘optics’ to use in the JWST light train to offer a viable route to discover the First Light sources.

Talk